The present invention is directed to a modularly structured ISDN (Integrated Services Digital Network) communication system.
Such modularly structured digital communication systems provide for connection of terminal equipment having a variety of performance features to one another and for the connection of such terminal equipment to communication networks, particularly public networks.
A communication system wherein, among other things, digital telephones, telecopiers, videotext stations and picture screen stations are connectable is disclosed in an article entitled "Telcom Report"--ISDN im Buero--1985 ISBN No. 3-8009-3846-4, Siemens AG.
In addition to a line switching unit to which these equipment are connected, what is referred to as an organizational data server unit that encompasses a system-operations-oriented function complex as well as various, optional data application functions are attributed to the modules of the communication system. The data application functions can be loaded and then activated. A special data server that can be used only for data applications can be integrated into the system instead of the organizational data server unit or in addition thereto. In this context, significant data application functions are as follows: